Solid state detector for very high dose rate radiation

Abstract

A solid state detector for ionizing radiation having a semiconductor substrate, a conductive metal layer, a first and a second active region, the first active region having a faster response time to ionizing radiation than the second active region. A first voltage is applied to the first active region and a second voltage applied to the second active region, the first and second voltages having opposite polarities and equal magnitudes. The solid state detector being configured to maintain a constant output voltage when not irradiated and to output an output voltage when irradiated, the output voltage being the time resolved sum of a first charge and a second charge accumulated by the two active regions, the first charge and the second charge having opposite polarities and configured to drain residual charges from the active regions.

1 . A solid state detector for ionizing radiation comprising:
 a substrate;   a metal layer deposited on the substrate, the metal layer being electrically conductive;   a first active region connected to a first input lead and a first output lead;   a second active region connected to a second input lead and a second output lead; and,   an output electrode;   wherein the first active region, the first input lead, the first output lead, the second active region, the second input lead, the second output lead, and the output electrode are formed in the metal layer;   wherein the first output lead, the second output lead, and the output electrode are electrically connected;   wherein the first active region is configured to have a first response time when irradiated with ionizing radiation and the second active region is configured to have a second response time when irradiated with the ionizing radiation;   wherein a first voltage is applied to the first input lead and a second voltage is applied to the second input lead;   wherein the first voltage is positive, the second voltage is negative, and the first voltage and the second voltage have an equal magnitude;   wherein the solid state detector is configured, when not being irradiated with ionizing radiation, to:
 maintain an output voltage at a constant level at the output electrode; 
 prevent the first active region from accumulating a first charge on the first output lead; and, 
 prevent the second active region from accumulating a second charge on the second output lead; 
   wherein the solid state detector is configured, when being irradiated with ionizing radiation, to:
 cause the first output lead to accumulate the first charge at the first response time and the second output lead to accumulate the second charge at the second response time; and, 
 output a time resolved sum of the first charge and the second charge as the output voltage at the output electrode; 
   wherein the first charge is positive and the second charge is negative; and,   wherein, when the ionizing radiation is removed, the solid state detector is configured to:
 enable one of the first charge or the second charge to drain a residual charge from the first active region and the second active region; and, 
 return the output voltage to the constant level. 
   
     
     
         2 . The solid state detector of  claim 1 ,
 wherein the first active region comprises a first metal pattern of digits having a first digit width and a first interdigital spacing;   wherein the first metal pattern is electrically connected to the first input lead and the first output lead;   wherein the second active region comprises a second metal pattern of digits having a second digit width and a second interdigital spacing;   wherein the second metal pattern is electrically connected to the second input lead and the second output lead;   wherein the substrate is configured to:
 be an insulator when the solid state detector is not being irradiated; and, 
 generate electrical charge carriers in the substrate when the solid state detector is irradiated with ionizing radiation; and, 
   wherein the first response time is faster than the second response time.   
     
     
         3 . The solid state detector of  claim 2 , wherein the second active region is larger than the first active region. 
     
     
         4 . The solid state detector of  claim 3 , wherein the second interdigital spacing is larger than the first interdigital spacing. 
     
     
         5 . The solid state detector of  claim 4 , wherein the first active region has a first diameter, and the second active region has a second diameter; and,
 wherein the second diameter is larger than the first diameter.   
     
     
         6 . The solid state detector of  claim 3 , wherein the output voltage is representative of an amount of the ionizing radiation incident on the solid state detector during a delay time; and,
 wherein the delay time is a time difference between the first response time and the second response time.   
     
     
         7 . The solid state detector of  claim 6 , wherein the substrate is a diamond substrate, and the first metal pattern of digits and the second metal pattern of digits comprise gold. 
     
     
         8 . The solid state detector of  claim 7 , wherein the metal layer is deposited on the substrate through electron beam deposition.